[ SOURCE: http://www.secureroot.com/security/advisories/9740472672.html ] -----BEGIN PGP SIGNED MESSAGE----- ============================================================================= FreeBSD-SA-00:67 Security Advisory FreeBSD, Inc. Topic: gnupg fails to correctly verify signatures Category: ports Module: gnupg Announced: 2000-11-10 Credits: Jim Small Affects: Ports collection prior to the correction date. Corrected: 2000-10-18 Vendor status: Updated version released FreeBSD only: NO I. Background GnuPG is an implementation of the PGP digital signature/encryption protocol. II. Problem Description Versions of gnupg prior to 1.04 fail to correctly verify multiple signatures contained in a single document. Only the first signature encountered is actually verified, meaning that other data with invalid signatures (e.g. data which has been tampered with by an attacker) will not be verified, and the entire document will be treated as having valid signatures. The gnupg port is not installed by default, nor is it "part of FreeBSD" as such: it is part of the FreeBSD ports collection, which contains over 4100 third-party applications in a ready-to-install format. The ports collections shipped with FreeBSD 3.5.1 and 4.1.1 are vulnerable to this problem since it was discovered after the releases, but it was corrected prior to the release of FreeBSD 4.2. FreeBSD makes no claim about the security of these third-party applications, although an effort is underway to provide a security audit of the most security-critical ports. III. Impact Documents containing multiple signed regions of data can be corrupted or tampered with by an attacker without detection, as long as the first signature in the document remains valid. IV. Workaround Deinstall the gnupg port/package, if you you have installed it. V. Solution One of the following: 1) Upgrade your entire ports collection and rebuild the gnupg port. 2) Deinstall the old package and install a new package dated after the correction date, obtained from the following directories: ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/security/gnupg-1.04.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/security/gnupg-1.04.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/security/gnupg-1.04.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/security/gnupg-1.04.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/security/gnupg-1.04.tgz 3) download a new port skeleton for the gnupg port from: http://www.freebsd.org/ports/ and use it to rebuild the port. 4) Use the portcheckout utility to automate option (3) above. The portcheckout port is available in /usr/ports/devel/portcheckout or the package can be obtained from: ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/devel/portcheckout-2.0.tgz ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/devel/portcheckout-2.0.tgz -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.4 (FreeBSD) Comment: For info see http://www.gnupg.org iQCVAwUBOgx6dlUuHi5z0oilAQEGaAP+KXIJlLBgF7tXXtLWcyJkhI6mAxgMyHEJ y+9RkI22mz7etMN1Nqm22Rj1cYBO99Q35lx4qJpuGftuRV+D9P6f5FbXMp+qhw24 K1t07eQhgiiNO1y9snvvEwwWtsHiosMFyIleFdbJwXoioqNsDFcByOwbG7zoEOOU BfDBTmKtPvQ= =1ZMA -----END PGP SIGNATURE-----